Nesocheiridium stellatum Beier, 1957

Krajcovicova, Katarina, Matyukhin, Aleksandr Vladimirovich & Jana Christophoryova,, 2020, Two new pseudoscorpion species (Pseudoscorpiones, Chthoniidae, Cheiridiidae) from the Tonga Islands, Polynesia, with a redescription of the genus Nesocheiridium, ZooKeys 927, pp. 37-51 : 37

Nesocheiridium stellatum Beier, 1957 Figs 1 , 4A , 5

Material examined.

Holotype: Northern Mariana Islands • ♂; Saipan, Mount Marpi [15.283, 145.817]; 40 m a.s.l.; 01 Mar. 1945; Henry S. Dybas leg.; under stone; FMNH-INS 0000 011 070.

Redescription.

Adult male (Figs 4A , 5 ). Integument coarsely granulate, dorsally granuloreticulate (Fig. 5B, C ). Vestitural setae arcuate with a small spine, often covered by a fine exudate giving them a leaf-like shape (Fig. 5A, D, E ). Carapace (Figs 4A , 5A ): 0.85 × longer than broad, subtriangular, distally narrowed; cucullus short; two distinct eyes with lenses; submedian transverse furrow deep; anterior disk laterally with perceptible swellings; posterior disk without a medial depression (Fig. 4A ); with 43 leaf-like setae (24 before furrow, 19 behind); with one pair of lyrifissures in ocular area. Chelicera (Fig. 5F ): 1.60 × longer than broad; four setae on hand, all setae acuminate; moveable finger with one short seta; fixed finger with three teeth near the tip; with two lyrifissures on hand; galea long, slender, stylet-like, without rami; serrula exterior with 10 blades; rallum consisting of four blades. Coxae (Fig. 5G ): coarsely granulate; chaetotaxy: manducatory process three acuminate setae, rest of palpal coxa with three acuminate and five leaf-like setae in anterior half; pedal coxae I six or seven acuminate setae, II seven acuminate setae, III six or seven acuminate setae, IV 9 or 10 acuminate setae. Lyrifissures: one or two on coxa III, 1 on coxa IV; maxillary lyrifissures not visible. Pedipalp (Fig. 5H-K ): coarsely granulate; trochanter with distinct dorsal hump; patella with distinct pedicel. Trochanter 1.40 ×, femur 4.13 ×, patella 2.89 ×, chela 3.62 ×, hand with pedicel 2.15 × longer than broad. Chela, including base of fixed finger, coarsely granulate (Fig. 5K ). Venom apparatus present in both fingers. Fixed chelal finger with seven trichobothria, moveable finger with two. Fixed finger with 16 flat marginal teeth; moveable finger with three flat marginal teeth. Fixed finger with granulate swelling mesally (Fig. 5I ), trichobothria ib and ist distad of swelling. Arrangement of trichobothria as in Figure 5J . Opisthosoma: Tergal chaetotaxy: 4+5: 6+6: 6+6: 6+7: 7+6: 7+7: 8+8: 7+7: 6+5: 5+5; I-X with leaf-like setae. Tergal lyrifissures I-X: 0+0: 1+1: 1+1: 1+1: 1+1: 1+1: 1+1: 0+0: 0+0: 0+0: 0+0. Tergal pores I-X: 0+0: 0+0: 0+0: 0+0: 2+2: 0+0: 2+1: 0+0: 0+3: 0+3. Sternal chaetotaxy (Fig. 5L ): 17: 10: 5+4: 7+6: 7+8: 7+7: 5+6: 7+6: 5+6: 3+3; II-VII with acuminate setae, VIII-XI with leaf-like setae. Sternal lyrifissures II-XI: 2: 2: 1+1: 0+0: 1+1: 1+1: 1+1: 1+1: 1+1: 0+0. Sternal pores II-XI: 4: 0: 7+8: 7+7: 5+6: 1+1: 0+0: 0+0: 1+2: 3+3. Anal opercula each with two short, acuminate setae. Genitalia not studied in detail. Leg I (Fig. 5M ): trochanter 0.86 ×, femoropatella 3.60 ×, tibia 3.00 ×, tarsus 4.33 × deeper than broad. Leg IV (Fig. 5N ): trochanter 1.43 ×, femoropatella 3.83 ×, tibia 3.60 ×, tarsus 5.67 × longer than deep. No tactile setae present; claws simple; arolia shorter than claws.

Dimensions (length/width or, for legs, length/depth) in mm. Body length 0.94. Pedipalp: trochanter 0.14/0.10, femur 0.33/0.08, patella 0.26/0.09, chela 0.47/0.13, hand with pedicel 0.28/0.13, hand without pedicel 0.23, moveable finger 0.21. Chelicera: 0.08/0.05, moveable finger 0.07. Carapace 0.34/0.40. Leg I: trochanter 0.06/0.07, femoropatella 0.18/0.05, tibia 0.12/0.04, tarsus 0.13/0.03. Leg IV: trochanter 0.10/0.07, femoropatella 0.23/0.06, tibia 0.18/0.05, tarsus 0.17/0.03.

Remarks.

Some of the morphometric values given here differ slightly from the original description ( Beier 1957) (e.g., body size 0.94 versus 0.90 mm; length of carapace 0.34 versus 0.32 mm; width of carapace 0.40 versus 0.37 mm).

Figures

Figure 1. Distribution of the studied species: Tyrannochthonius eua sp. nov. (yellow triangle), Nesocheiridium stellatum (white circle), N. onevai sp. nov. (red circle).

Figure 3. Tyrannochthonius eua sp. nov., holotype male, dorsal A carapace B coxae C coxal spines D right chelicera E right chela, showing trichobothrial pattern F chaetotaxy of genital area (sternites II-III). Abbreviations: trichobothria of moveable chelal finger: t - terminal, b - basal, sb - subbasal, st - subterminal; trichobothria of fixed chelal finger: dx - duplex trichobothria, et - exterior terminal, it - interior terminal, est - exterior subterminal, ist - interior subterminal, esb - exterior subbasal, eb - exterior basal, isb - interior subbasal, ib - interior basal. Scale bars: 0.1 mm.

Figure 4. Nesocheiridium species, dorsal view A N. stellatum, holotype male B N. onevai sp. nov., holotype female. Arrow indicates widening of palpal patella. Scale bar: 0.5 mm.

Figure 5. Nesocheiridium stellatum, holotype male A carapace B, C details of granulation types on carapace D leaf-like seta E arcuate seta with a small spine F right chelicera G coxae H right palp minus chela I chelal fingers, ventro-lateral view, showing swelling on fixed finger J right chela K detail of granulation on chela L chaetotaxy of genital area (sternites II-III) M right leg I N right leg IV. Abbreviations as for Figure 3. Scale bars: 0.1 mm.